Sausages are an ancient prepared food. In the olden days efficient butchers saved the various scraps of organ meats, blood and fat, salted them, stuffed them into tubular casings, and preserved them by curing, drying, or smoking.

Traditional sausage casings are cleaned pig intestines, however today they are often collagen or cellulose.

Modern sausage meat is ground pork, beef, or veal. In the USA fat content is legally limited to 30%, 35% or 50% depending on the type of sausage. The USDA defines the content for various sausages and generally prohibits the fillers or extenders used in English cuisine where they add up to 25% of bread and starch.

Breakfast or Country Sausage is made from ground pork mixed with pepper, sage, and other spices. It is commonly sliced into patties and pan-fried, or cooked and crumbled into scrambled eggs or gravy.

Sausage Roll is a sheet of puff pastry formed into tubes around sausage meat and glazed with egg or milk before being baked and served either hot or cold.

Merguez is a red, spicy sausage from Morocco, Algeria, Tunisia and Libya. It is made of lamb, beef, or a mixture of both flavored with a wide range of spices, such as sumac, paprika, Cayenne pepper, or a hot chili paste. It is stuffed into a lamb casing and traditionally eaten grilled with couscous.

Boerewors, or farmer's sausage, of South Africa is made of game and beef, mixed with pork or lamb and with a high percentage of fat. Coriander and vinegar are the seasoning ingredients. The long continuous spiral sausage is traditionally cooked on a barbecue.

Loukaniko of Greece is a pork sausage flavored with orange peel and fennel seed.

Salsiccia of Italy is made of pure pork spiced with fennel seeds and chilli in the south, or black pepper and garlic in the north.

Sucuk of Turkey and the Balkans is made from beef that is fermented then spiced with garlic and pepper and lightly smoked. The taste is extremely hot, spicy and greasy.

Blood sausages are made in America, Europa and Asia by cooking pig, cattle, sheep, duck, or goat blood with a filler until it is thick enough to congeal. In Europe and America typical fillers are meat, fat, suet, bread, cornmeal, sweet potato, onion, chestnuts, barley, and oatmeal. In Spain, Portugal and Asia, potato is replaced with rice.

Frankfurters and Hot Dogs are the most common pre-cooked sausages in the USA. Frankfurters are more mild, Hot Dogs are more heavily seasoned.

Other popular ready-to-eat sausages, often eaten in sandwiches, include salami, American-style bologna, Lebanon bologna, prasky, liverwurst, and head cheese.